The present invention relates to a combined medicine for the purpose of treating inflammatory diseases and more particularly to a combined medicine useful for treating diseases of a joint with inflammation.
It has been known that hyaluronic acid or its salt is effective to some kinds of arthropathies in clinical and fundamental tests. The theoretical bases are as follows: (1) Hyaluronic acid is one of the main components of joint liquid. In the case of rheumatoid arthritis and osreoarthritis which are included in arthropathy, the hyaluronic acid contained in the joint liquid has a reduced molecular weight and a reduced concentration. (2) As the main pharmacological actions of hyaluronic acid, there are exemplified an action of covering the surface of a cartilage, an inhibitory action on the liberation of proteoglycan, which action is exhibited by the hyaluronic acid migrated into a cartilage matrix, and an improving action on the spinnability of the joint liquid.
However, most of the reported clinical cases wherein hyaluronic acid was applied are osteoarthritis and rheumatoid arthritis and its applicable range is relatively narrow. Further, although symptoms such as pain and stiffness become in serious problem in the treatment of joint diseases, hyaluronic acid does not possess any direct activity of improving such symptoms.
Anti-inflammatory agents are widely used in the clinical treatment of arthropathy. The reason therefor is presumed that many kinds of arthropathies involves inflammation. The reason why nonsteroidal anti-inflammatory agents are especially widely used is presumed that they have strong analgesic activity.
However, when anti-inflammatory agents are administered in a usual clinical method such as oral administration, administration using suppository, subcutaneous or intramuscular administration, side effects such as the inflammation and ulcer of digestive system, and diarrhea tend to develop because the drug reaches its effective concentration not only at a part to be treated but also in tissues of the whole body including blood. Further the development of the side effects is promoted due to the fact that a large amount of dose is required for the treatment because of the distribution of the drug over the whole body and the fact that the administration period is prolonged because most arthropathies are chronic. For the reasons, a sufficient amount of the drug required for the treatment cannot be administered or the administration is obliged to be interrupted, which results in failure of a suitable treatment. Consequently, there are many cases wherein the condition of the disease is worsened.
It is an object of the present invention to provide an inflammation-treating agent, in particular, which is capable of curing inflammation in joint diseases and possesses the activity of improving symptoms such as pain and stiffness.
Another object of the invention is to provide an efficient inflammation-treating agent, in particular, which does not develop any side effect even when a sufficient amount thereof required for the treatment of joint diseases is administered.
These and other objects of the present invention will become apparent from the description hereinafter.